Phosphorus-28

Properties and data of the isotope ²⁸P.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Phosphorus-28 is a radioisotope of the chemical element phosphorus, which has 13 neutrons in its atomic nucleus in addition to the element-specific 15 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 28. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁸P is exclusively for academic purposes.

The isotope phosphorus-28 was first produced by the charge exchange reaction ²⁸Si(p,n)²⁸P during the irradiation of natural Si samples with protons accelerated to 20 MeV [1, (1977)].

See also: List of individual Phosphorus isotopes (and general data sources).

General data

Name of the isotope:Phosphorus-28; P-28Symbol:²⁸P or 2815PMass number A:28 (= number of nucleons)Atomic number Z:15 (= number of protons)Neutrons N:13Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):0.86666666666667 (= neutron-proton ratio)Neutron excess (N-Z):-2Isotopic mass:27.9923265(12) u (atomic weight of Phosphorus-28)Nuclide mass:27.9840979 u (calculated nuclear mass without electrons)Mass excess:-7.14782 MeVMass defect:0.237692888 u (per nucleus)Nuclear binding energy:221.40949901 MeV (per nucleus)
7.90748211 MeV (average binding energy per nucleon)Separation energy:S_N = 14.560(9) MeV (first neutron)
S_P = 2.0523(12) MeV (first proton)Half-life:270.3(5) msDecay constant λ:2.5643624881981 s^-1Specific activity α:5.71961189624 × 10⁺²² Bq g^-1
1545841053039.7 Ci g^-1Spin and parity:
(nuclear angular momentum)3+Magnetic dipole moment:μ(μ_N) = 0.312(3)Nuclear g-factor:g_l = 0.104Mirror nucleus:Aluminium-28Year of discovery:1953

Radioactive Decay

Half-life T_½ = 270.3(5) ms respectively 2.703 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy
EC/β⁺	²⁸Si	99.998 %	14.3449(11) MeV
β⁺, p	²⁷Al	0.0013(4) %	14.334(3) MeV
β⁺, α	²⁴Mg	0.00086(25) %	4,3618(11) MeV

Parent Nuclides

Direct parent isotope is: ²⁸S.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 13) and isobaric (same nucleon number A = 28) with Phosphorus-28. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 13	Isobar A = 28
5	¹⁸B
6	¹⁹C
7	²⁰N
8	²¹O	²⁸O
9	²²F	²⁸F
10	²³Ne	²⁸Ne
11	²⁴Na	²⁸Na
12	²⁵Mg	²⁸Mg
13	²⁶Al	²⁸Al
14	²⁷Si	²⁸Si
15	²⁸P	²⁸P
16	²⁹S	²⁸S
17	³⁰Cl	²⁸Cl
18	³¹Ar
19	³²K

External data and identifiers

Adopted Levels, Gammas:NuDat 28P

Literature and References

[1] - Neel W. Glass, Louis K. Jensen, J. Reginald Richardson:
The Short-Lived Radioisotopes P²⁸ and Cl³².
In: Physical Review, 90, 320, (1953), DOI 10.1103/PhysRev.90.320.2.

[2] - S. W. Breckon, A. Henrikson, J. S. Foster, W. M. Martin:
The Radioactive Isotopes Al²⁴, P²⁸, Cl³².
In: Canadian Journal of Physics, 32, 3, (1954), DOI 10.1139/p54-020.